Amend regex to account for new release labels
Amend regex to account for new release labels

We're planning to add labels that look like
"committed-online-fy18.q2", so `TrelloHelper::RELEASE_LABEL_REGEX` and
`TrelloHelper#sortable_card_label` need to be updated to parse and
sort cards with these new style labels.

dobbymoodge/sprint_tools,dobbymoodge/sprint_tools,danmcp/sprint_tools,openshift/sprint_tools,openshift/sprint_tools,danmcp/sprint_tools